- ID:
- ivo://CDS.VizieR/J/AJ/140/844
- Title:
- UCAC3 proper motion survey
- Short Name:
- J/AJ/140/844
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents 442 new proper motion stellar systems in the southern sky between declinations -90{deg} and -47{deg} with 0.40"/yr>{mu}>=0.18"/yr. These systems constitute a 25.3% increase in new systems for the same region of the sky covered by previous SuperCOSMOS RECONS (SCR) searches that used Schmidt plates as the primary source of discovery. Among the new systems are 25 multiples, plus an additional 7 new common proper motion (CPM) companions to previously known primaries. All stars have been discovered using the third U.S. Naval Observatory (USNO) CCD Astrograph Catalog (UCAC3). A comparison of the UCAC3 proper motions to those from the Hipparcos, Tycho-2, Southern Proper Motion (SPM4), and SuperCOSMOS efforts is presented and shows that UCAC3 provides similar values and precision to the first three surveys.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/745/118
- Title:
- UCAC3 proper motion survey. II. -47<DEC<0{deg}
- Short Name:
- J/ApJ/745/118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 474 new proper motion stellar systems (500 objects) in the southern sky having no previously known components, with 0.40"/yr>{mu}>=0.18"/yr between declinations -47{deg} and 0{deg}. In this second paper utilizing the U.S. Naval Observatory third CCD Astrograph Catalog (UCAC3) we complete our sweep of the southern sky for objects in the proper motion range targeted by this survey with R magnitudes ranging from 9.80 to 19.61. The new systems contribute a ~16% increase in the number of new stellar systems for the same region of sky reported in previous SuperCOSMOS Research Consortium On Nearby Stars (RECONS) surveys. Among the newly discovered stellar systems are 16 multiples, plus an additional ten components that are new common proper motion companions to previously known objects. A comparison of UCAC3 proper motions to those from Hipparcos, Tycho-2, Southern Proper Motion, and SuperCOSMOS indicates that all proper motions are consistent to ~10mas/yr, with the exception of SuperCOSMOS. Distance estimates are derived for all stellar systems having SuperCOSMOS Sky Survey B_J_, R_59F_, and I_IVN_ plate magnitudes and Two Micron All Sky Survey (2MASS) infrared photometry. We find five new red dwarf systems estimated to be within 25pc. These discoveries support results from previous proper motion surveys suggesting that more nearby stellar systems are to be found, particularly in the fainter, slower moving samples. In this second paper utilizing the UCAC3 we complete our sweep of the southern sky for objects in the proper motion range targeted by this survey with R magnitudes ranging from 9.80 to 19.61.
433. UniDAM results
- ID:
- ivo://CDS.VizieR/J/A+A/604/A108
- Title:
- UniDAM results
- Short Name:
- J/A+A/604/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galactic archaeology, the study of the formation and evolution of the Milky Way by reconstructing its past from its current constituents, requires precise and accurate knowledge of stellar parameters for as many stars as possible. To achieve this, a number of large spectroscopic surveys have been undertaken and are still ongoing. So far consortia carrying out the different spectroscopic surveys have used different tools to determine stellar parameters of stars from their derived effective temperatures, surface gravities, and metallicities; the parameters can be combined with photometric, astrometric, interferometric, or asteroseismic information. Here we aim to homogenise the stellar characterisation by applying a unified tool to a large set of publicly available spectrophotometric data. We used spectroscopic data from a variety of large surveys combined with infrared photometry from 2MASS and AllWISE and compared these in a Bayesian manner with PARSEC isochrones to derive probability density functions (PDFs) for stellar masses, ages, and distances. We treated PDFs of pre-helium-core burning, helium-core burning, and post helium-core burning solutions as well as different peaks in multimodal PDFs (i.e. each unimodal sub-PDF) of the different evolutionary phases separately. For over 2.5 million stars we report mass, age, and distance estimates for each evolutionary phase and unimodal sub-PDF. We report Gaussian, skewed, Gaussian, truncated Gaussian, modified truncated exponential distribution or truncated Student's t-distribution functions to represent each sub-PDF, allowing us to reconstruct detailed PDFs. Comparisons with stellar parameter estimates from the literature show good agreement within uncertainties. We present UniDAM, the unified tool applicable to spectrophotometric data of different surveys, to obtain a homogenised set of stellar parameters.
- ID:
- ivo://CDS.VizieR/J/AJ/157/211
- Title:
- Unresolved binaries in TESS with speckle imaging
- Short Name:
- J/AJ/157/211
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Transiting Exoplanet Survey Satellite (TESS) is conducting a two-year wide-field survey searching for transiting exoplanets around nearby bright stars that will be ideal for follow-up characterization. To facilitate studies of planet compositions and atmospheric properties, accurate and precise planetary radii need to be derived from the transit light curves. Since 40%-50% of exoplanet host stars are in multiple star systems, however, the observed transit depth may be diluted by the flux of a companion star, causing the radius of the planet to be underestimated. High angular resolution imaging can detect companion stars that are not resolved in the TESS Input Catalog, or by seeing-limited photometry, to validate exoplanet candidates and derive accurate planetary radii. We examine the population of stellar companions that will be detectable around TESS planet candidate host stars, and those that will remain undetected, by applying the detection limits of speckle imaging to the simulated host star populations of Sullivan et al. (2015, J/ApJ/809/77) and Barclay et al. (2018, J/ApJS/239/2). By detecting companions with contrasts of {Delta}m~<7-9 and separations of ~0.02"-1.2", speckle imaging can detect companion stars as faint as early M stars around A-F stars and stars as faint as mid-M around G-M stars, as well as up to 99% of the expected binary star distribution for systems located within a few hundred parsecs.
- ID:
- ivo://CDS.VizieR/J/A+A/514/A59
- Title:
- uvby{beta} photometry in Carina. II
- Short Name:
- J/A+A/514/A59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In recent years a significant development has become evident in the study of the stellar structure of the Galactic disk. This is especially true for the 3rd Galactic quadrant, where the stellar population was extensively investigated beyond 10kpc, revealing details about the warped geometry of the thin and thick disks and outer arm. The 4th Galactic quadrant offers even better opportunity to follow the distribution of the young stellar populace to a large distance, since the line of sight is parallel to the largest single segment of a spiral arm seen from our position in the Galaxy: the Carina spiral feature. This paper further contributes to the study of the structure of the Galactic disk in the direction of Carina field utilizing homogeneous photometric distances of a sample of about 600 bright early-type stars seen in this direction up to 6kpc. The derived stellar distances are based on uvby{beta} photometry. All O and B type stars with uvby{beta} data presently available are included in the study.
- ID:
- ivo://CDS.VizieR/J/A+AS/130/477
- Title:
- uvby{beta} photometry in 3 EUV shadow directions
- Short Name:
- J/A+AS/130/477
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the uvby{beta} data used to locate the dust and derive distances for nearby diffuse interstellar clouds in the EUV shadows lb27-31, lb165-32 and lb329+46 discovered by the Extreme Ultraviolet Explorer. The photometrically derived parallaxes of our program stars are compared to the parallaxes listed in the Hipparcos Catalog. Within the photometric distance limit of 150pc, the photometric parallaxes of 21 ``normal" stars are consistent with the Hipparcos measurements within an uncertainty of 15%. Much as expected for the Stroemgren system. Since all program stars are brighter than V=~11.5 most of them are included in the Tycho photometry. For our sample of ~200 stars we find V_by_ and V_T_ to be consistent. Few stars are common to published uvby{beta} catalogs, ~10, V and the indices compare well apart from {beta} where a zero point difference of 11mmag is noticed.
- ID:
- ivo://CDS.VizieR/J/AJ/156/78
- Title:
- 44 validated planets from K2 Campaign 10
- Short Name:
- J/AJ/156/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 44 validated planets from the 10th observing campaign of the NASA K2 mission, as well as high-resolution spectroscopy and speckle imaging follow-up observations. These 44 planets come from an initial set of 72 vetted candidates, which we subjected to a validation process incorporating pixel-level analyses, light curve analyses, observational constraints, and statistical false positive probabilities. Our validated planet sample has median values of R_p_=2.2 R_{Earth}_, P_orb_=6.9 days, T_eq_=890 K, and J=11.2 mag. Of particular interest are four ultra-short period planets (P_orb_~<1 day), 16 planets smaller than 2 R_{Earth}_, and two planets with large predicted amplitude atmospheric transmission features orbiting infrared-bright stars. We also present 27 planet candidates, most of which are likely to be real and worthy of further observations. Our validated planet sample includes 24 new discoveries and has enhanced the number of currently known super-Earths (R_p_~1-2 R_{Earth}_), sub-Neptunes (R_p_~2-4 R_{Earth}_), and sub-Saturns (R_p_~4-8 R_{Earth}_) orbiting bright stars (J=8-10 mag) by ~4%, ~17%, and ~11%, respectively.
- ID:
- ivo://CDS.VizieR/J/ApJ/551/973
- Title:
- Variables near SN 1991T in NGC 4527
- Short Name:
- J/ApJ/551/973
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Repeated imaging observations have been made of NGC 4527 with the Hubble Space Telescope between 1999 April and June, over an interval of 69 days. Images were obtained on 12 epochs in the F555W band and on five epochs in the F814W band. The galaxy hosted the Type Ia supernova SN 1991T, which showed relatively unusual behaviour by having both an abnormal spectrum near light maximum, and a slower declining light curve than the prototypical Branch-normal SNe Ia. A total of 86 variables that are putative Cepheids have been found, with periods ranging from 7.4 days to over 70 days.
- ID:
- ivo://CDS.VizieR/J/A+A/651/A47
- Title:
- Variable stars in VVV globulars. II.
- Short Name:
- J/A+A/651/A47
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The Galactic globular clusters (GGCs) located in the inner regions of the Milky Way suffer from high extinction that makes their observation challenging. High densities of field stars in their surroundings complicate their study even more. The VISTA Variables in the Via Lactea (VVV) survey provides a way to explore these GGCs in the near-infrared where extinction effects are highly diminished. We conduct a search for variable stars in several inner GGCs, taking advantage of the unique multi-epoch, wide-field, near-infrared photometry provided by the VVV survey. We are especially interested in detecting classical pulsators that will help us constrain the physical parameters of these GGCs. In this paper, the second of a series, we focus on NGC 6656 (M 22), NGC 6626 (M 28), NGC 6569, and NGC 6441; these four massive GGCs have known variable sources, but quite different metallicities. We also revisit 2MASS-GC 02 and Terzan 10, the two GGCs studied in the first paper of this series. We present an improved method and a new parameter that efficiently identify variable candidates in the GGCs. We also use the proper motions of those detected variable candidates and their positions in the sky and in the color-magnitude diagrams to assign membership to the GGCs. We identify and parametrize in the near-infrared numerous variable sources in the studied GGCs, cataloging tens of previously undetected variable stars. We recover many known classical pulsators in these clusters, including the vast majority of their fundamental mode RR Lyrae. We use these pulsators to obtain distances and extinctions toward these objects. Recalibrated period-luminosity-metallicity relations for the RR Lyrae bring the distances to these GGCs to a closer agreement with those reported by Gaia, except for NGC 6441, which is an uncommon Oosterhoff III GGC. Recovered proper motions for these GGCs also agree with those reported by Gaia, except for 2MASS-GC 02, the most reddened GGC in our sample, where the VVV near-infrared measurements provide a more accurate determination of its proper motions.
- ID:
- ivo://CDS.VizieR/J/A+A/512/A37
- Title:
- Velocities of 43 nearby L dwarfs
- Short Name:
- J/A+A/512/A37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial velocity measurements of a sample of L0-L8 dwarfs observed with VLT/UVES and Keck/HIRES. We combine these measurements with distance and proper motion from the literature to determine space motions for 43 of our targets. We identify nine candidate members of young moving groups, which have ages of 50-600Myr according to their space motion.
